CVE-2025-66376

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2025-66376
StatePUBLISHED
Assignermitre
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-01-05 15:15:44 UTC
Updated2026-10-07 10:10:00 UTC
DescriptionZimbra Collaboration (ZCS) 10 before 10.0.18 and 10.1 before 10.1.13 allows Classic UI stored XSS via Cascading Style Sheets (CSS) @import directives in an HTML e-mail message.

Risk And Classification

Primary CVSS: v3.1 6.1 MEDIUM from [email protected]

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

EPSS: 0.202270000 probability, percentile 0.974470000 (date 2026-10-20)

CISA KEV: Listed on 2026-03-18; due 2026-04-01; ransomware use Unknown

Problem Types: CWE-79 | CWE-79 CWE-79 Improper Neutralization of Input During Web Page Generation (XSS or 'Cross-site Scripting')

VersionSourceTypeScoreSeverityVector
3.1[email protected]Primary6.1MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
3.1[email protected]Secondary7.2HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N
3.1CNADECLARED7.2HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
Required
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

CISA Known Exploited Vulnerability

VendorSynacor
ProductZimbra Collaboration Suite (ZCS)
NameSynacor Zimbra Collaboration Suite (ZCS) Cross-Site Scripting Vulnerability
Required ActionApply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Noteshttps://wiki.zimbra.com/wiki/Zimbra_Security_Advisories ; https://nvd.nist.gov/vuln/detail/CVE-2025-66376

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Application Synacor Zimbra Collaboration Suite All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Zimbra Collaboration affected 10.0 10.0.18 custom Not specified
CNA Zimbra Collaboration affected 10.1 10.1.13 custom Not specified

References

ReferenceSourceLinkTags
wiki.zimbra.com/wiki/Zimbra_Responsible_Disclosure_Policy [email protected] wiki.zimbra.com Product
wiki.zimbra.com/wiki/Zimbra_Releases/10.0.18 [email protected] wiki.zimbra.com Release Notes
www.cisa.gov/known-exploited-vulnerabilities-catalog 134c704f-9b21-4f2e-91b3-4a467353bcc0 www.cisa.gov US Government Resource
wiki.zimbra.com/wiki/Zimbra_Releases/10.1.13 [email protected] wiki.zimbra.com Release Notes
wiki.zimbra.com/wiki/Security_Center [email protected] wiki.zimbra.com Release Notes, Vendor Advisory
wiki.zimbra.com/wiki/Zimbra_Security_Advisories [email protected] wiki.zimbra.com Vendor Advisory
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis
CISA Known Exploited Vulnerabilities catalog CISA www.cisa.gov kev

Additional Advisory Data

SourceTimeEvent
ADP2026-03-18T00:00:00.000ZCVE-2025-66376 added to CISA KEV

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